metadata search gives 500

## Describe the bug
when searching an image by its taken date i get 500

## Steps to reproduce
```shell
curl --location --request REPORT 'https://host.docker.internal:9200/remote.php/dav/spaces' \
--header 'Content-Type: application/xml' \
--header 'Authorization: Basic bWFyaWU6cmFkaW9hY3Rpdml0eQ==' \
--data '

photo.exposureDenominator=178

"'
```

## Expected behavior
if query is incorrect it should give `400` bad request

## Actual behavior
A clear and concise description of what happened.
```xml

{"id":"com.owncloud.api.search","code":500,"detail":"can not compile the query","status":"Internal Server Error"}

```

## Setup
Please describe how you started the server and provide a list of relevant environment variables or configuration files.

```console
OCIS_XXX=somevalue
OCIS_YYY=somevalue
PROXY_XXX=somevalue
```

## Additional context
Add any other context about the problem here.